The present invention relates to shift controllers for power transmissions employed in motor vehicles and particularly automatic transmissions employed in light trucks and passenger cars.
Heretofore, it has been desirable to have electronic controlling of the shifting in the vehicle automatic transmission and particularly desirable to integrate the electronic control circuitry with that employed for engine operational control in order to optimize the driveability and shift response of the transmission.
In known vehicle automatic transmissions, a plurality of solenoid operated shift control valves are mounted on a manifold which is attached to the transmission housing; and, the manifold is ported to communicate with corresponding fluid passage ports formed on the deck of the transmission housing. Heretofore, such known electro-hydraulic control manifold assemblies have utilized metal for the manifold in order to provide the requisite stiffness when exposed to the hydraulic fluid pressure in the passages formed in the transmission deck. However, a metal manifold has required costly machining operations to provide the valving chamber cavities and porting arrangements for receiving the solenoid valves and for making hydraulic connection to the ports on the transmission housing.
Thus, it has been desired to reduce the cost of manufacturing the manifold assembly without increasing the complexity or jeopardizing the reliability and resistance to the hydraulic pressures encountered.
The present invention provides an electro hydraulic controller having a plurality of solenoid operated valves mounted on a manifold assembly which has a manifold block formed of non-metallic material attached by fasteners to a base formed of metallic material with the manifold ported to receive fluid through the base into respective individual valving cavities for the solenoid valves and the return flow through the base through outlet ports associated with each valve. A sealing gasket is disposed between the manifold block and the base and secured therebetween for sealing the flow ports therein. A gasket is provided under the base for attachment of the assembly to appropriate fluid passages formed on a vehicle transmission housing.
The invention thus provides for a one-piece manifold block which is formed of non-metallic material which may be molded with the ports and valving chambers thereon formed to finished dimensions, and thus eliminates the requirement for costly machining operations and thereby provides significant cost savings in the manufacture of the assembly. The manifold block in the present invention is preferably formed of plastic material preferably partially filled with particulate glass material; and, may be fabricated preferably by molding to xe2x80x9cNet Shapexe2x80x9d without costly machining operations to achieve critical dimensions.
The base is preferably cast from metallic material and does not require subsequent machining. In the present practice of the invention it has been found satisfactory to form the base of material selected from the group consisting essentially of (a) aluminum, (b) magnesium, (c) steel stamped from sheet stock and (d) equivalents thereof.